This invention relates to a cleaning unit for a device for harvesting long agricultural products such as grass, straw, pulses, biomass products and the like, a harvesting device which uses the cleaning unit and a method for improving the harvesting device (by installing said cleaning unit).
Harvesting devices are normally used for harvesting grass, straw or hay (cut by other machines) from the ground or for harvesting pulses; or in any case, for harvesting like agricultural products (generally plants) which are long and thin in shape.
For this purpose, they are connected to a pulling vehicle (such as a tractor or a self-propelled agricultural machine) which is used to tow them.
Prior art harvesting devices have a main axis of extension which, during use, remains transversal to the axis of movement of the pulling vehicle. To lift the agricultural products from the ground and move them (prior to unloading), harvesting devices use a plurality of harvesting elements associated therewith and driven by a movement system. The movement system is generally driven by a Cardan joint or the like which, through a power take-off, draws drive power from the engine of the pulling vehicle.
Each harvesting element is in turn provided with one or more juxtaposed tines. The harvesting elements (and the respective tines) are generally arranged around the main axis of extension in rows parallel to the main axis of extension itself. Each harvesting element (and the respective tines) is driven by the movement system along a closed trajectory which surrounds the main axis of extension. The tines are straight elements with one end coupled (either directly or by means of parts of the respective harvesting element) to the movement system and the other end free.
Operatively downstream of the harvesting elements, devices of this type generally also comprise means for unloading the agricultural products harvested, usually consisting of movement devices, such as conveyor belts, chain conveyors or screw conveyors, located along the axis of extension of the harvesting device immediately downstream of the harvesting elements, in order to transport the agricultural products to the sides of the pulling vehicle.
It should be noted that each of the unloading means has a respective axis of movement, generally parallel to the main axis of extension of the frame, that is, transversal to the advancing axis.
In light of this, prior art unloading means extend between their two opposite ends, one of which, in use, constitutes a product release zone.
At that end, the continuous flow of agricultural products provides a good guarantee of keeping the mechanical parts and the unloading means clean because it is difficult for the products to get entangled between the moving parts.
At the other end, on the other hand, where the flow starts and is, obviously, much slower, the agricultural products harvested tend to get trapped between the moving parts and to build up, thereby interfering with the movement of the unloading means and with the operation of the pick-up means.
This problem becomes even more critical when the unloading means are of a relatively unforceful type such as, for example, chain conveyors or conveyor belts (with or without tracks).
It is known that agricultural machines are not frequently cleaned, and thus, any “self-cleaning” feature, that is, the ability of moving mechanical parts to remain as clean as possible automatically, is crucial and any improvement in this respect can play a decisive role in the marketability of an agricultural implement.